1. Field of the Invention
This invention is directed to lighting fixtures, in general, and to lighting fixtures which provide reduction of temperature, reduction of unwanted glare from side light loss and, as well, can use directional extension mounting mechanisms while using CMH or similar lamps, in particular.
2. Prior Art
There are many light fixtures known in the art which can be classified into a number of categories such as track lighting, recessed down lights and the like. The broadest category is decorative fixtures, such as ceiling and surface mounted fixtures, wall mounted fixtures, pendant mounted fixtures and the like. Many of these fixtures permit replacement of conventional incandescent lamps.
In addition, there are many types of reflective glass covers known in the art. These covers typically include an aluminized glass reflector, support necks attached thereto, and appropriate threaded collars for mounting the reflectors over the light source, also referred to as a lamp. However, these reflectors are often limited in terms of size and utility by the fixture in which the reflector is mounted.
In retail spaces, the goal is, generally, to draw the customer's attention to the merchandise being displayed, not to the lighting fixtures. In down light applications, the elimination of stray light lamp imaging and light glare reflection off the inside the reflector/trim assembly is extremely important. Even small amounts of radiant side light, from the edges of the screw-based reflector lamps, is undesirable.
The aesthetic lighting design principles are virtually the same for new construction and/or retrofit application.
It is also useful to understand the evolution of energy efficient retrofit lighting over the past number of years, and to reflect on the changes that have taken place as new lighting technologies have been introduce into the market place.
U.S. Pat. No. 5,073,845 (Aubrey) illustrates a socket assembly used with a one piece aluminized glass reflector. This glass reflector lens, commonly used in the lamp industry to manufacture incandescent light bulbs (R30, R40, PAR-38 reflector flood and spot lights are examples) are fitted with threaded aluminum collars and modified to accept a single-ended compact fluorescent lamp or HID screw-base lamp as a retrofit for an existing incandescent fixture. However, objectionable side glare off the edges of the front lens was an unwanted by product of this design.
Adapter socket cup housings were made of formed aluminum for these situations. Within the cup was a fluorescent lamp holder designed to accept a compact, single-ended, two-pin low-wattage lamp or, alternatively, a female screw-based lamp holder to accept Edison-based high pressure sodium (HPS) screw-base lamps. The cosmetic appearance of not seeing the fluorescent or HPS lamp is desirable. However, considerable heat is generated by these lamps. Also, the one piece glass reflector trapped heat around the lamp tubes, causing the lamp bulb wall temperature to run higher than in an open reflector. To resolve these problems, ventilation holes were provided in the bottom of the socket cup. This solution, however, resulted in unwanted “light leak” out the back of the assembly. Even though unwanted light leak was produced, because of holes in the bottom of the socket cup, the ventilation holes were necessary to cool the adaptors.
With the advent of higher wattage (26/32 watt) compact fluorescent lamps, it was found that a substantial amount of heat was generated but not dissipated adequately via the aluminum structure and vent holes in the socket cup assembly to make the adaptor function properly. Therefore, an aluminum heat sink with a plurality of fins was developed as described in U.S. Pat. No. 6,974,233 (Aubrey).
Recently, lamp manufacturers have introduced highly efficient (64 lumens per watt) one-piece PAR 38 metal halide lamps. Over the last few years smaller size PAR lamps have been introduced and CMH lamps have become very popular.
Small tubular shaped, single ended “T-CMH” (ceramic metal halide) lamps have been recently introduced into the market place. These lamps are arch-tubes shielded within a tubular clear glass envelope and are simply the light producing element that, historically, has been molded into the glass PAR reflector/lens configurations during the manufacturing process that is used to produce Edison screw based lamps. In other words, these are bare tube metal halide lamps, without a reflector and without an Edison screw base attachment. In place of the traditional Edison screw-shell base attachments, specific pin coupling lamp bases have been incorporated.
The “T-CMH” lamps have been relatively slow to gain acceptance with fixture manufacturers and end-user customers. To change the lamp in a small fixture, one must be able to grasp the relatively small diameter lamp with two fingers and either pull or twist it to remove it from the socket/reflector assembly contained with in the fixture.
Since fixtures have, typically, been designed to accept off-the-shelf, one-piece, screw-in light bulbs, with Edison screw-base, lighting element, reflector and lens as an integral product, there is a limit as to how small the fixture lens opening or depth of recess can be and still allow one to easily change the lamp that is contained within the fixture.
Of additional concern, as fixtures have become smaller and smaller, unwanted excessive heat is usually generated and, of great importance, is the elimination of unwanted radiant side light. This unwanted light leak through ventilation holes in socket assembles or in other parts of the fixtures are byproducts of these openings in the fixtures that are necessary to ventilate the fixture and prevent overheating thereof.
Edison base screw-in PAR metal halide lamps are constructed as an integral unit, with an assembly of a parabolic reflector in a precise relationship to the arch tube. Even a slight variation in the positioning of the arch tube within the reflector assembly will greatly affect the maximum light efficiency of the light produced from the assembly.
Lamp manufacturers control the location of the arch-tube within a parabolic reflector in the manufacturing process by fusing the glass components together in the proper orientation to assure maximum light output.
Likewise, fixture manufactures, using the single ended CMH lamps, traditionally control the location of the arch-tube in relationship to a parabolic reflector by making the socket/parabolic assembly a one piece, unitized assembly, so that no variations will occur in the manufacturing process. The lamp holder structure, contained within the fixture typically has a parabolic reflector attached to it.
The above description outlines, briefly, the advances in light source (lamp) technology and the difficulties produced thereby.